Interval fasting as a method of wellness or weight loss has become popular in recent years. There is a huge difference between short periods of not eating and prolonged fasting. The course of physiological processes changes, and these changes do not always have a positive effect on health. Therefore, it is important to understand how exactly the body reacts to the absence of food and what the popular fasting schemes are.
How the body reacts to a prolonged absence of food
- The first 24 hours without food are relatively uneventful. Blood sugar levels drop, and the body switches to glycogen reserves stored in the liver and muscles. Glycogen is a kind of “storehouse” of glucose, the main source of energy. This reserve is enough for a short time, about 24 hours. After that, the body starts to look for alternative sources of “fuel”.
- The next step is the breakdown of fatty tissue. Fats are converted into ketone bodies that the brain and other organs can use for energy. This process is called ketosis. This results in the active use of fatty tissue for energy. At this stage, some people may notice a decrease in appetite and a burst of energy. But ketosis has a downside: the increased concentration of ketone bodies can lead to intoxication, bad breath, headaches and weakness. After two days, the glycogen reserves run out. Next, the body begins to extract energy from muscles, breaking down proteins to amino acids. As a result, not only fat but also muscle mass is lost.
- When fasting longer than 3-4 days, the body is exhausted. Electrolyte balance is disturbed, which leads to arrhythmias, convulsions, loss of consciousness. Prolonged fasting leads to the use of the body’s own tissues as energy sources. Tissues of the heart, liver, kidneys are destroyed. If this process is prolonged, all organs and systems go into austerity mode. Metabolism slows down, heart rate decreases, blood pressure drops, and immunity decreases.
- Starvation longer than 10-14 days results in irreversible changes. Recovery from such stress takes months, and sometimes leads to chronic diseases. Prolonged lack of nutrients leads to the development of a number of deficiency conditions – iron deficiency anemia, deficiency of B vitamins, folic acid, vitamin C, potassium, magnesium, zinc, etc.
A separate danger is refeeding syndrome. Refeeding after a long fast causes electrolyte imbalance, edema and can be fatal. Therefore, withdrawal from starvation should be gradual, under the supervision of a doctor.
What is interval fasting?
Interval fasting is an eating regimen that alternates periods of eating and fasting. The idea is to give the body long “windows” without food so that it can switch to using its own energy stores, including fat stores.
There are several variations of interval fasting:
- 12/12 scheme – a mild and comfortable mode for beginners (it is difficult to consider this format as a variant of fasting, it is rather a physiological pause, taking into account the time of night sleep);
- 14/10 – a person fasts for 14 hours, and for 10 hours can eat as usual;
- 16/8 – 8-hour “gap” for food intake and 16 hours of fasting, when only water or herbal tea can be drunk;
- 20/4 – eating is only possible for 4 hours a day;
- 5/2 – five days a week a person eats as usual, and two days – significantly limits calories (up to 500-600 kcal).
When choosing your nutrition option, it is important to take into account the state of health, the presence of diseases of the digestive tract, the level of physical activity, and the usual daily routine.
The benefits and harms of interval fasting
Intermittent fasting may be a suitable eating style for some people. It may also be an option for weight loss diet planning, as limiting the time interval in which meals are allowed helps to reduce caloric intake. However, there is no scientific evidence to support the benefits of interval fasting over a balanced, moderate-calorie diet.
Interval fasting can lead to slower metabolism, loss of muscle mass, impaired digestion, and hormonal imbalance. Some people complain of weakness, dizziness, headaches, insomnia when using interval fasting. Women may experience menstrual irregularities and men may experience a decrease in testosterone.
A particular dietary regimen also affects mood. Short-term interval fasting sometimes causes a burst of energy due to the formation of ketone bodies and the release of adrenaline. But long-term restrictions provoke irritability, anxiety, and apathy due to increased levels of cortisol (stress hormone). For a number of people interval fasting can be a provoking factor in the development of eating disorders, if you notice an increased fixation on thoughts of food and weight loss, please give up this practice.
Interval fasting is not suitable for everyone. Contraindications include pregnancy, breastfeeding, type 1 diabetes, gastrointestinal diseases, weight deficiency, chronic diseases of the urinary system, eating disorders and eating disorders.
Myths and misconceptions about interval fasting
Interval fasting is often associated with the works of the scientist – molecular biologist Yoshinori Osumi, who in 2016 received the Nobel Prize “for the discovery of autophagy mechanisms”. However, the scientist himself states that he is not involved in human nutrition, was not involved in the development of the diet, and does not make recommendations regarding fasting.
Proponents of interval fasting claim the rejuvenating effects of this style of eating, but there are still few reliable, long-term studies of this method of weight loss and its effects on human health. It is likely that a balanced diet and regular meals are just as good as interval fasting.
Psychological aspects of interval fasting
In addition to physiological changes, interval fasting also affects a person’s psycho-emotional state. For some people, fasting can be a source of stress, anxiety and irritability, especially if it causes intense feelings of hunger or the need for constant dietary control. Some people notice that the feeling of hunger becomes unbearable, especially in the initial stages, which can cause mood swings and even depression. It is important to remember that fasting should be adapted to individual needs, and if it causes psychological discomfort, it is worth consulting a specialist.
Conclusion
Regular fasting, including interval fasting, can have both positive and negative health effects. It can promote weight loss and improve metabolism, but requires careful consideration, especially for people with certain medical conditions or special needs. It is important to realize that prolonged fasting or uncontrolled use of strict regimens can lead to serious physical and psychological disturbances. Therefore, before you begin practicing interval fasting or any other dietary restriction, you should consult your doctor and consider your own health condition. The key is moderation and an informed approach to avoid possible risks and maximize the use of this practice to improve health.
